Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/16—Making expandable particles
  • C08J9/18—Making expandable particles by impregnating polymer particles with the blowing agent
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
  • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
  • C08J9/14—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent organic
  • C08J9/149—Mixtures of blowing agents covered by more than one of the groups C08J9/141 - C08J9/143
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/16—Making expandable particles
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
  • C08L25/02—Homopolymers or copolymers of hydrocarbons
  • C08L25/04—Homopolymers or copolymers of styrene
  • C08L25/08—Copolymers of styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
  • C08J2325/02—Homopolymers or copolymers of hydrocarbons
  • C08J2325/04—Homopolymers or copolymers of styrene
  • C08J2325/06—Polystyrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2371/00—Characterised by the use of polyethers obtained by reactions forming an ether link in the main chain; Derivatives of such polymers
  • C08J2371/08—Polyethers derived from hydroxy compounds or from their metallic derivatives
  • C08J2371/10—Polyethers derived from hydroxy compounds or from their metallic derivatives from phenols
  • C08J2371/12—Polyphenylene oxides
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S521/00—Synthetic resins or natural rubbers -- part of the class 520 series
  • Y10S521/91—Plural blowing agents for producing nonpolyurethane cellular products

Definitions

• DE-A No. 32 20 856 discloses a process for the preparation of foams having high heat distortion resistance, in which a mixture from 95 to 20% by weight of a styrene polymer and from 5 to 80% by weight of a polyphenylene ether is mixed in the melt with pentane and the mixture is then extruded.
• foams of this type can only be produced in the form of extrudates or sheets. The process is unsuitable for the production of foam moldings of any desired shape.
• EP-A No. 241 258 discloses a process for the preparation of foams having particularly low density, in which a mixture of not less than 50% by weight of polystyrene, from 0.06 to 15% by weight of a polyphenylene ether and from 0.05 to 3% by weight of an aromatic phosphate is mixed in the melt with a fluorochlorohydrocarbon as a blowing agent and the mixture is then extruded.
• the aromatic phosphate acts as a plasticizer and leads to foams having unsatisfactory heat distortion resistance.
• the fluorochlorohydrocarbons used as blowing agents pollute the environment, since they damage the ozone layer of the atmosphere. Furthermore, the extrusion process is unsuitable for the production of foam moldings of any desired shape.
• an expandable polymer in particle form which is based on styrene polymers and polyphenylene ethers and contains, as a blowing agent, a mixture of aliphatic or cycloaliphatic hydrocarbons on the one hand and aromatic hydrocarbons, alcohols, ketones, ethers, esters and/or chlorohydrocarbons on the other hand.
• the present invention accordingly provides expandable polymers in particle form, containing
• the present invention furthermore relates to a process for the preparation of such expandable polymers in particle form, in which an intimate mixture of (a) a styrene polymer, (b) a polyphenylene ether and, if required, (d) conventional additives in effective amounts, in particle form in aqueous suspension, is impregnated with (c) a blowing agent mixture consisting of
• chlorohydrocarbon of 1 or 2 carbon atoms and 2 or 3 chlorine atoms
• the present invention furthermore relates to a process for the preparation of foam particles having a density of from 5 to 200 kg/m 3 , in which either the hot suspension obtained in the preparation of the expandable polymers is let down into an atmosphere under low pressure or the suspension is cooled and the particles that contain blowing agent are then isolated and are expanded by treatment with a hot gas.
• styrene polymers are polystyrene and copolymers of styrene which contain not less than 50% by weight of styrene as copolymerized units.
• suitable comonomers are ⁇ -methylstyrene, styrenes halogenated in the nucleus, acrylonitrile, esters of (meth)acrylic acid of 1 to 8 carbon atoms, N-vinylcarbazole, maleic anhydride and/or small amounts of compounds having two polymerizable double bonds, such as butadiene, divinylbenzene or butanediol diacrylate.
• styrene polymers are furthermore the high impact polystyrenes, i.e. polymers which contain not less than 50% by weight of copolymerized styrene and, as a grafting base or in a finely divided state, a rubber, such as polybutadiene, polyisoprene, styrene/butadiene rubber, acrylate rubber or the like.
• high impact polystyrenes i.e. polymers which contain not less than 50% by weight of copolymerized styrene and, as a grafting base or in a finely divided state, a rubber, such as polybutadiene, polyisoprene, styrene/butadiene rubber, acrylate rubber or the like.
• ABS and ASA styrene copolymers are also suitable.
• the expandable polymers contain the styrene polymer in general in an amount of from 20 to 94.9, preferably from 30 to 93, in particular from 40 to 80, % by weight.
• a preferably used polyphenylene ether is the commercial poly(2,6-dimethyl-1,4-phenylene oxide), which is used in an amount of from 0.1 to 75, preferably from 2 to 65, % by weight. When up to 10% by weight are used, the resulting products give, on expansion, foam particles having a particularly low bulk density. The heat distortion resistance of the foams produced from the products increases with increasing content of polyphenylene ether.
• the expandable polymers of the invention contain, as a blowing agent, a mixture of a component (c1) having only an insignificant plasticizing effect and a component (c2) having an important plasticizing effect.
• a component (c1) having only an insignificant plasticizing effect and a component (c2) having an important plasticizing effect.
• Aliphatic or cycloaliphatic saturated hydrocarbons of 3 to 7 carbon atoms, such as propane, butane, n-pentane, isopentane, hexane, heptane, cyclohexane or methylcyclohexane, or mixtures of these are used as component (c1).
• Aromatic saturated hydrocarbons of 7 or 8 carbon atoms such as toluene or xylene, alcohols of 2 to 4 carbon atoms, such as ethanol, propanol, isopropanol, n-butanol, isobutanol or tert-butanol, ketones of 3 to 5 carbon atoms, such as acetone, methyl ethyl ketone or diethyl ketone, cyclic ethers of 4 to 6 carbon atoms, such as dioxane, dimethyldioxane or tetrahydrofuran, aliphatic ethers of 4 to 6 carbon atoms, such as diethyl ether or diisopropyl ether, esters of 4 to 6 carbon atoms, such as ethyl acetate, methyl propionate, propyl acetate or butyl acetate, and/or chlorohydrocarbons of 1 or 2 carbon atoms and 2 or 3 chlorine
• the blowing agent is present in the expandable polymers in an amount of from 5 to 20, preferably from 7 to 18, % by weight.
• the weight ratio of component (c1) to component (c2) is from 50:1 to 1:1, preferably from 20:1 to 2:1.
• the plasticizing blowing agent component (c2 ) reduces the softening point of the mixture of styrene polymer and polyphenylene oxide and thus makes it possible to reduce the temperature at which the polymer mixture is impregnated with the blowing agent.
• the reduction of this preparation temperature is also associated with a corresponding reduction in the pressure during impregnation.
• Component (c2 ) also reduces the softening point of the expandable polymers and permits expansion at a lower temperature and with a higher throughput per unit time. After expansion of the expandable polymers, the foam particles still contain, as a rule, small amounts of the blowing agent component (c2). They can therefore be particularly readily welded to give moldings.
• the expandable polymers may furthermore contain conventional assistants in the usual effective amounts, e.g. dyes, pigments, antistatic agents, lubricants, flameproofing agents and fillers.
• conventional assistants e.g. dyes, pigments, antistatic agents, lubricants, flameproofing agents and fillers.
• Suitable flameproofing agents are hexabromocyclododecane, monochloropentabromocyclohexane, trisnonylphenyl phosphite and triphenylphosphine oxide.
• Flameproofing agents are generally used in an effective amount of from 0.5 to 8, preferably from 2 to 6, % by weight, based on the sum of the polymers (a) and (b).
• the individual components are virtually homogeneously distributed in the expandable polymers.
• the said polymers are in the form of particles and are, as a rule, spherical, bead-like or drop-like. They generally have a mean diameter of from 0.2 to 4, preferably from 0.3 to 3, mm.
• novel expandable polymers are prepared by impregnating the styrene polymer/polyphenylene ether particles in aqueous suspension with the blowing agent mixture at elevated temperatures and under superatmospheric pressure.
• This procedure starts from an intimate mixture of styrene polymer with the polyphenylene ether and, if required, additives, as is obtained, for example, by mixing the components in an extruder.
• the mixture should be in particle form and have a mean diameter of from 0.2 to 4, preferably from 0.3 to 3, mm.
• the granules obtainable by hot face cutting or cold face cutting of the extrudates are suitable for this purpose.
• Impregnation with the blowing agent is carried out in a pressure-resistant stirred vessel.
• the procedure is carried out in aqueous suspension, in general using from 90 to 350, preferably from 100 to 300, parts of water per 100 parts of polymer.
• the procedure is advantageously carried out in the presence of known suspending agents, such as very finely divided alumina, basic magnesium carbonate, basic zinc carbonate, calcium carbonate, calcium phosphate or kieselguhr.
• suspending agents such as very finely divided alumina, basic magnesium carbonate, basic zinc carbonate, calcium carbonate, calcium phosphate or kieselguhr.
• conventional water-soluble polymers which considerably increase the viscosity of the aqueous phase, e.g. polyvinylpyrrolidone and polyvinyl alcohol, are suitable dispersants.
• the finely divided emulsion polymer of the liquid phase (serum) of a styrene emulsion polymerization is also suitable.
• the dispersant is used in general in amounts of from 0.1 to 10, preferably from 0.1 to 4.0, parts per 100 parts of water.
• the dispersion is heated together with the blowing agent to a temperature at which the polymer softens.
• this softening temperature is, as a rule, lower than the softening temperature of the pure polymer mixture.
• the optimum temperature can easily be determined by a preliminary experiment. It is from 100° to 250° C.
• the pressure during the impregnation is essentially determined by the vapor pressure of the water and of the blowing agent and is in general from 8 to 60 bar.
• the dispersion After the softening point has been reached, the dispersion is kept at this temperature for some time, for example from 1 to 100 minutes. Thereafter, it is cooled, and the expandable polymer is isolated from the suspension, if necessary after washing and drying.
• foam particles can also be produced directly, without intermediate isolation of the expandable polymers, by discharging the hot dispersion from the lower end of the pressure kettle and letting down the dispersion while keeping the pressure and the temperature in the kettle virtually constant. The particles expand spontaneously when let down to low pressure. They are then isolated from the aqueous phase and if necessary washed and dried.
• Foam particles are also obtained when the expandable polymer is treated with a hot gas, for example with steam or heated nitrogen or air.
• a hot gas for example with steam or heated nitrogen or air.
• the temperature of the gas is above the softening point of the expandable polymers.
• expansion can be carried out in a conventional expander at steam temperatures of about 100° C.
• Higher PPE contents require steam temperatures of up to 180° C. and preheated preexpanders.
• the foam particles can be further expanded by treating them once again or several times more with hot gas.
• the density of the resulting foam particles is from 5 to 200, in particular from 10 to 100, kg/m 3 .
• the foam particles obtained are very suitable for the production of foam moldings of any desired shape.
• they are introduced in a conventional manner into a mold which does not have a gas-tight seal, and are heated therein to above the softening point. During this procedure, the particles soften, expand and become welded to form a molding which conforms to the shape of the inside of the mold.
• the foam particles and the moldings produced therefrom have good heat distortion resistance and a low density. They are used as insulating materials and packaging and for a number of further applications where heat insulation and cold insulation, high rigidity, heat distortion resistance and low density are desirable.
• Example 2 The experiments are carried out similarly to Example 1, except that, instead of tetrahydrofuran, methyl ethyl ketone is used as the plasticizing blowing agent and the impregnating temperature is increased to 130° C. Details are shown in Table 1. The expansion properties of the granules containing blowing agent are summarized in Table 2.
• Example 7 The experiment is carried out similarly to Example 7, except that subsequent impregnation is carried out using only pentane, without the addition of a plasticizing blowing agent (2).
• the resulting material has poorer expansion properties, characterized by an increased bulk density of the expanded particles. Details are shown in Table 2.
• the foam moldings are each kept at 80° C. in a drying oven for 3 days in order to expel residual plasticizer.
• 270 parts of water, 6 parts of the dispersant tricalcium phosphate and 0.03 part of sodium dodecylbenzenesulfonate, as a surfactant, are introduced into a pressure-resistant stirred vessel.
• 100 parts of a polymer mixture granulated to a particle weight of 1.7 mg and consisting of 60% by weight of polyphenylene ether and 40% by weight of a high impact polystyrene which contains 9% of butadiene rubber are added to the stirred mixture.
• the polymer mixture has a melt flow index of 7 [g/10 min], measured at 250° C./21.6 kg.
• the resulting foam particles are treated with nitric acid to remove the tricalcium phosphate and are finally washed neutral and dried.
• the directly formed foam particles can be postexpanded expanded to lower bulk densities with superheated steam at 175° C. in the course of 1.5 minutes in an expander preheated to 170° C.
• the foam particles obtained in Examples 13, 14, 15 and 17 to 21 are converted into moldings in the course of 3 minutes with steam superheated at 175° C., in molds which are not gas-tight and which are preheated to 170°-180° C.
• the cavities between the spherical particles are filled during the expansion process.
• the moldings obtained have gross densities of up to 10% below or up to 20% above the bulk density used, i.e. from 25 to 80 g/l.
• a molding which is produced from foam particles having a bulk density of 50 g/l (experiment 14) and which has a gross density of 55 g/l possesses a compressive strength of 0.4 MPa at 10% compression (DIN 53,421) and a heat distortion resistance of 171° C. (DIN 53,424).

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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• 1988
  • 1988-05-25 DE DE3817631A patent/DE3817631A1/de not_active Withdrawn
• 1989
  • 1989-05-13 EP EP89108685A patent/EP0343473B1/de not_active Expired - Lifetime
  • 1989-05-13 DE DE8989108685T patent/DE58902323D1/de not_active Expired - Lifetime
  • 1989-05-13 ES ES89108685T patent/ES2052808T3/es not_active Expired - Lifetime
  • 1989-05-19 US US07/354,230 patent/US4927859A/en not_active Expired - Fee Related
  • 1989-05-24 JP JP1129032A patent/JP2688248B2/ja not_active Expired - Lifetime
  • 1989-05-25 KR KR1019890007043A patent/KR970008856B1/ko active IP Right Grant

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